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Bolex diopter focus problem


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#1 Curtis Alexander

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Posted 29 December 2010 - 08:56 PM

Hi, I rented a super 16mm modified bolex from my local film co-op and I cannot get it into focus just by looking through the eyepiece at the ground glass and manipulating the diopter. I'm doing this with no lens on. Also with my glasses on and off. I asked my girlfriend to try as well and she could not get it into focus either. (Where in this case, focus means trying to get the markings and the dust and such on the ground glass into focus.)

What I'm wondering is...is this me? Am I doing something wrong? Or is there possibly something wrong with the camera? I've used this camera before, but not for a year, so perhaps it's not been maintained, or I've forgot how to set it up right?

Any suggestions would be helpful. I'm not sure what model of bolex it is.

Thanks,
Curtis.
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#2 Jeremy Rumas

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Posted 29 December 2010 - 09:18 PM

Have you tried pointing the camera towards a bright light when doing this? I always have to do it this way, or point it toward the sky during the day...when you do get it in focus you will see the grain of the ground glass, looks like film grain almost. Bolex's are pretty hard to see clearly through.
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#3 Curtis Alexander

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Posted 29 December 2010 - 09:44 PM

Have you tried pointing the camera towards a bright light when doing this? I always have to do it this way, or point it toward the sky during the day...when you do get it in focus you will see the grain of the ground glass, looks like film grain almost. Bolex's are pretty hard to see clearly through.


Yup, I'm looking at a bright light, tried a couple different spots out into the sky. Can't get it into perfect focus though.
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#4 Chris Millar

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Posted 29 December 2010 - 10:08 PM

Sometimes the diopter adjustment thingy can get loose - especially after its been forced - if I recall it loosens something similar to a grub screw kind of set up and then just spins freely, if not that exactly, something about as technical and boring ;)

If its a proper super16 conversion and/or an RX4, RX5, SB, SBM, EBM or EL it should have the 13x finder which I know if you look at the eyecup and rotate the darth vader thingy you can see it rack in and out - does yours ? The 10x finder probably works this way too, I just have no memory of experience with them to draw upon.

If yes, then there is something wrong inside and there are a few bits in the optical path that could be putting it outta whack... If no then thats it, time to either fix it or take it back to the owners

How does the top of the prism look ? (in other words, the GG/mask) - also, the angle between the finder assembly on top of the camera and the camera itself should be pretty parallel, is it ?

I guess if you were to put a lens on it with a lens cap or somehow otherwise black out the front and look through the finder then see any light it would show issues with the connection between the little portal at the front of the finder in that if it were off angle which would cause focus isses then it'd prob let light through also.

Do you have jewellers drivers ? (if you have a magazine mount you'll need one with a looooong shank) - take off the top and have a look, its not too nasty in there - just make sure the driver fits snug or you'll strip the screw head and have to drill it out (zero fun)
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#5 Curtis Alexander

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Posted 29 December 2010 - 11:29 PM

Sometimes the diopter adjustment thingy can get loose - especially after its been forced - if I recall it loosens something similar to a grub screw kind of set up and then just spins freely, if not that exactly, something about as technical and boring ;)

If its a proper super16 conversion and/or an RX4, RX5, SB, SBM, EBM or EL it should have the 13x finder which I know if you look at the eyecup and rotate the darth vader thingy you can see it rack in and out - does yours ? The 10x finder probably works this way too, I just have no memory of experience with them to draw upon.


Re darth vader thingy...if when I say diopter and you say darth vader thingy, :), we both mean the eyepiece on the far left of the attached img with the white markings, then yup, I can alter the focus using it, that I can never get it racked in, ie. never in focus. Close, but not quite.

bolexs16.jpg
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#6 Chris Millar

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Posted 30 December 2010 - 12:40 AM

Yup - that darth vader thingy - looks like his shoulder pads

so it wont go in far enough ? into the minus zone ... hmmm, I think if people try to force (heh heh) the diopter when the locking pin thingy on the top is still in you can shear off or simply loosen the thingy bob that does the focusing a bit so when you push it into the minus zone it moves the whole thing out of reference so you can never get that negative again without pushing it back and tightening it/fxing it. You'll have to excuse the lack of technical terms, it's just hard to remember, let alone describe if I could see it right now - anyways, you do need to open it up to fix it, and you've got an RX5 there - boo! - you need a driver that get through that hole...

Yeh, that really long hole - boring huh.

Unless, well, maybe try simply pushing it in - go all the way negative, then give it a reasonable shove... Does it move on its own ?
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#7 Curtis Alexander

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Posted 30 December 2010 - 12:49 PM

Yup - that darth vader thingy - looks like his shoulder pads

so it wont go in far enough ? into the minus zone ... hmmm, I think if people try to force (heh heh) the diopter when the locking pin thingy on the top is still in you can shear off or simply loosen the thingy bob that does the focusing a bit so when you push it into the minus zone it moves the whole thing out of reference so you can never get that negative again without pushing it back and tightening it/fxing it. You'll have to excuse the lack of technical terms, it's just hard to remember, let alone describe if I could see it right now - anyways, you do need to open it up to fix it, and you've got an RX5 there - boo! - you need a driver that get through that hole...

Yeh, that really long hole - boring huh.

Unless, well, maybe try simply pushing it in - go all the way negative, then give it a reasonable shove... Does it move on its own ?


Hmm, yeah, it seems so close in the negative but I just can't get all the way. I can't try moving it more without fear of breaking it. I think I will just return it in the new year and let them know I couldn't get focus. I've used this camera a few times before and have had no trouble at all with focus, so I think it need some maintenance.

Thanks so much for all the replies!

Edited by Curtis Alexander, 30 December 2010 - 12:50 PM.

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#8 Chris Millar

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Posted 30 December 2010 - 05:21 PM

Hmm, yeah, it seems so close in the negative but I just can't get all the way. I can't try moving it more without fear of breaking it. I think I will just return it in the new year and let them know I couldn't get focus. I've used this camera a few times before and have had no trouble at all with focus, so I think it need some maintenance.

Thanks so much for all the replies!


Bummer - maybe you or someone you know has some spare optics laying about ? I don't know what you'd need but it couldn't hurt trying a magnifying glass or whatever, maybe the focus will pop somewhere in the range of adjustment you have there...

If you're mechanically minded I still recommend opening it up - its pretty self explanatory in there, no irreversible disasterisation.
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